scholarly journals Genetic parameters and performance of papaya genotypes to black spot resistance (Asperisporium caricae)

Author(s):  
Ramon Moraes ◽  
Marcelo Vivas ◽  
Janieli Maganha Silva Vivas ◽  
Rogério Figueiredo Daher ◽  
Geraldo Amaral Gravina ◽  
...  

Estimation of genetic parameters such as genetic variability of germplasm allows inferring genotype-enviromental interaction for a given variable. The information is important for the process of choosing the variables to be applied to the superior genotype selection. This study aimed at evaluating characteristics related to genetic resistance of papaya to black spot during time testing, as well as estimating genetic parameters associated with some characteristics. The experiment was carried out in RCBD design at Agua Limpa farm, Espirito Santo state, Brazil, using six genotypes: ‘STZ-03’, ‘SS-PT’, ‘Golden’ (‘Solo’ group) ‘Maradol’ (‘Formosa’ group) ‘STA-04’ ‘STA-10’ (landraces), and four repetitions. The 6 treatments were arranged in single row, spacing 2 m between rows and 1.5 m within plants. Nine evaluations were performed during 9 months. We quantified plants on a monthly basis for the characters such as symptom appearance of black spot (FS) on leaves; the incidence of leaves with black spot symptoms (IBS); the severity of black spot on the fifth leaf (SBS5F) and on the leaf with axil attached to the first open flower (SBSFO). By means of the evaluation values, we built a Boxplot graphic to characterize the magnitude of the variables and to describe the dispersion of the data set throughout the evaluations. Analysis of variance, genetic parameter estimate and comparative test of mean were also conducted. The Boxplot graphic allowed classification and magnitude of the variables and described the dispersion of the data set during evaluations. The results showed that SBS5F and the SBSFO were the characteristics that generated reliable results to select genotypes in all evaluations. They showed high H² (Coefficient of genotypic determination), CVg (Coefficient of genotypic variance), CVr (Coefficient of relative variance) and AS (Selective accuracy). The months July, August, September and October showed higher representativeness to evaluate attributes related to resistance to black spot in papaya leaves.

2001 ◽  
Vol 73 (2) ◽  
pp. 229-240 ◽  
Author(s):  
H. N. Kadarmideen ◽  
R. Rekaya ◽  
D. Gianola

AbstractA Bayesian threshold-liability model with Markov chain Monte Carlo techniques was used to infer genetic parameters for clinical mastitis records collected on Holstein-Friesian cows by one of the United Kingdom’s national recording schemes. Four data sets were created to investigate the effect of data sampling methods on genetic parameter estimates for first and multi-lactation cows, separately. The data sets were: (1) cows with complete first lactations only (8671 cows); (2) all cows, with first lactations whether complete or incomplete (10 967 cows); (3) cows with complete multi-lactations (32 948 records); and (4) all cows with multiple lactations whether complete or incomplete (44 268 records). A Gaussian mixed linear model with sire effects was adopted for liability. Explanatory variables included in the model varied for each data set. Analyses were conducted using Gibbs sampling and estimates were on the liability scale. Posterior means of heritability for clinical mastitis were higher for first lactations (0·11 and 0·10 for data sets 1 and 2, respectively) than for multiple lactations (0·09 and 0·07, for data sets 3 and 4, respectively). For multiple lactations, estimates of permanent environmental variance were higher for complete than incomplete lactations. Repeatability was 0·21 and 0·17 for data sets 3 and 4, respectively. This suggests the existence of effects, other than additive genetic effects, on susceptibility to mastitis that are common to all lactations. In first or multi-lactation data sets, heritability was proportionately 0·10 to 0·19 lower for data sets with all records (in which case the models had days in milk as a covariate) than for data with only complete lactation records (models without days in milk as a covariate). This suggests an effect of data sampling on genetic parameter estimates. The regression of liability on days in milk differed from zero, indicating that the probability of mastitis is higher for longer lactations, as expected. Results also indicated that a regression on days in milk should be included in a model for genetic evaluation of sires for mastitis resistance based on records in progress.


Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.


Author(s):  
Navaldeep Kaur ◽  
Lesley K. Fellows ◽  
Marie-Josée Brouillette ◽  
Nancy Mayo

Abstract Objectives: In the neuroHIV literature, cognitive reserve has most often been operationalized using education, occupation, and IQ. The effects of other cognitively stimulating activities that might be more amenable to interventions have been little studied. The purpose of this study was to develop an index of cognitive reserve in people with HIV, combining multiple indicators of cognitively stimulating lifetime experiences into a single value. Methods: The data set was obtained from a Canadian longitudinal study (N = 856). Potential indicators of cognitive reserve captured at the study entry included education, occupation, engagement in six cognitively stimulating activities, number of languages spoken, and social resources. Cognitive performance was measured using a computerized test battery. A cognitive reserve index was formulated using logistic regression weights. For the evidence on concurrent and predictive validity of the index, the measures of cognition and self-reported everyday functioning were each regressed on the index scores at study entry and at the last follow-up [mean duration: 25.9 months (SD 7.2)], respectively. Corresponding regression coefficients and 95% confidence intervals (CIs) were computed. Results: Professional sports [odds ratio (OR): 2.9; 95% CI 0.59–14.7], visual and performance arts (any level of engagement), professional/amateur music, complex video gaming and competitive games, and travel outside North America were associated with higher cognitive functioning. The effects of cognitive reserve on the outcomes at the last follow-up visit were closely similar to those at study entry. Conclusion: This work contributes evidence toward the relative benefit of engaging in specific cognitively stimulating life experiences in HIV.


2018 ◽  
Vol 63 (No. 6) ◽  
pp. 230-236 ◽  
Author(s):  
J.O. Rosa ◽  
G.C. Venturini ◽  
T.C.S. Chud ◽  
B.C. Pires ◽  
M.E. Buzanskas ◽  
...  

This study estimated the genetic parameters for reproductive and performance traits and determined which ones can be used as selection criteria for egg production in laying hens using the Bayesian inference. The data of 1894 animals from three generations of White Leghorn laying hens were analyzed for fertility (FERT), hatchability (HATC), and birth rate measurements at 60 weeks of age (BIRTH), body weight at 16 and 60 weeks of age (BW16 and BW60), age at sexual maturity (ASM), egg height/width ratio, weight, and density at 28, 36, and 40 weeks of age (RHW28, RHW36, RHW40, WEGG28, WEGG36, WEGG40, DENS28, DENS36, and DENS40, respectively) traits. The genetic parameters were estimated by the Bayesian inference method of multi-trait animal model. The model included the additive and residual genetic random effects and the fixed effects of generation. The a posteriori mean distributions of the heritability estimates for reproductive traits ranged from 0.14 ± 0.003 (HATC) to 0.22 ± 0.005 (FERT) and performance from 0.07 ± 0.001 (RHW28) to 0.42 ± 0.001 (WEGG40). The a posteriori mean distributions of the genetic correlation between reproductive traits ranged from 0.18 ± 0.026 (FERT and HACT) to 0.79 ± 0.007 (FERT and BIRTH) and those related to performance ranged from –0.49 ± 0.001 (WEGG36 and DENS36) to 0.75 ± 0.003 (DENS28 and DENS36). Reproductive and performance traits showed enough additive genetic variability to respond to selection, except for RHW28. This trait alone would have little impact on the genetic gain because environmental factors would have a higher impact compared to those from the additive genetic factors. Based on the results of this study, the selection applied on the BIRTH trait can be indicated to improve FERT and HATC of eggs. Furthermore, the use of the WEGG40 could improve egg quality in this population.


2014 ◽  
Vol 52 (5) ◽  
pp. 897-915 ◽  
Author(s):  
Yan Chen ◽  
Yiwei Jiang ◽  
Chengqi Wang ◽  
Wen Chung Hsu

Purpose – The purpose of this paper is to examine how firm resources and diversification strategy explain the performance consequences of internationalization of emerging market enterprises. Design/methodology/approach – The paper conducts a regression analysis by using a novel panel data set comprising of 685 listed Chinese firms over the period of 2008-2011. Findings – The results show that the relationship between internationalization and performance is inverse U-shaped. Further, marketing resources play a greater role in enhancing the performance effects of internationalization than technological resources do. Related product diversification enhances the performance effects, while unrelated product diversification does the contrary. Research limitations/implications – The study focusses on listed firms in one country, and as a result, the findings cannot be generalized to non-listed firms and firms in other countries. Practical implications – This paper offers guidelines for international managers to improve performance of internationalization by developing a particular type of resources and diversification strategy. Originality/value – This paper extends the literature on the functional form of the internationalization-performance relationship, and further suggests that the analysis of the performance consequences of internationalization should go beyond the nexus between internationalization and performance, and focusses on firm-specific resources and strategies that may facilitate or constrain the performance effects of internationalization.


2015 ◽  
Vol 42 (12) ◽  
pp. 1071-1089
Author(s):  
Alan Chan ◽  
Bruce G. Fawcett ◽  
Shu-Kam Lee

Purpose – Church giving and attendance are two important indicators of church health and performance. In the literature, they are usually understood to be simultaneously determined. The purpose of this paper is to estimate if there a sustainable church congregation size using Wintrobe’s (1998) dictatorship model. The authors want to examine the impact of youth and adult ministry as well. Design/methodology/approach – Using the data collected from among Canadian Baptist churches in Eastern Canada, this study investigates the factors affecting the level of the two indicators by the panel-instrumental variable technique. Applying Wintrobe’s (1998) political economy model on dictatorship, the equilibrium level of worship attendance and giving is predicted. Findings – Through various simulation exercises, the actual church congregation sizes is approximately 50 percent of the predicted value, implying inefficiency and misallocation of church resources. The paper concludes with insights on effective ways church leaders can allocate scarce resources to promote growth within churches. Originality/value – The authors are the only researchers getting the permission from the Atlantic Canada Baptist Convention to use their mega data set on church giving and congregation sizes as per the authors’ knowledge. The authors are also applying a theoretical model on dictatorship to religious/not for profits organizations.


1997 ◽  
Vol 1997 ◽  
pp. 31-31
Author(s):  
A.D. Hall ◽  
W.G. Hill ◽  
P.R. Bampton ◽  
A.J. Webb

Until recently, to enable accurate recording of feed intake, pigs were kept in individual pens. The advent of electronic feeders has allowed accurate records of feed intake and feeding patterns in group housing which is more similar to that found in the production environment. The objectives of this study were to estimate genetic parameters for these feeding pattern traits and their correlations with production traits to show potential benefits in selection.


2021 ◽  
pp. 1-45
Author(s):  
Benjamin Leard ◽  
Joshua Linn ◽  
Yichen Christy Zhou

Abstract During historical periods in which US fuel economy standards were unchanging, automakers increased performance but not fuel economy, contrasting with recent periods of tightening standards and rising fuel economy. This paper evaluates the welfare consequences of automakers forgoing performance increases to raise fuel economy as standards have tightened since 2012. Using a unique data set and a novel approach to account for fuel economy and performance endogeneity, we find undervaluation of fuel cost savings and high valuation of performance. Welfare costs of forgone performance approximately equal expected fuel savings benefits, suggesting approximately zero net private consumer benefit from tightened standards.


2018 ◽  
Vol 19 (5) ◽  
pp. 915-934 ◽  
Author(s):  
Gianluca Ginesti ◽  
Adele Caldarelli ◽  
Annamaria Zampella

Purpose The purpose of this paper is to analyse the impact of intellectual capital (IC) on the reputation and performance of Italian companies. Design/methodology/approach The paper exploits a unique data set of 452 non-listed companies that obtained a reputational assessment from the Italian Competition Authority (ICA). To test the hypotheses, this study implemented several regression analyses. Findings Results support the argument that human capital efficiency is a key driver of corporate reputation. Findings also reveal that companies, which obtained reputational rating under ICA scrutiny, show a positive relationship between IC elements and various measures of financial performance. Research limitations/implications The study focuses on a single country; it is not free from the imprecisions of Pulic’s VAIC model. Practical implications This paper recommends companies that are interested to achieve a robust reputation should consider the human capital as a strategic intangible asset. Second, the results suggest that companies with an ICA reputational rating are able to leverage their intangibles to potentiate performance and competitiveness. Originality/value This is the first empirical investigation on the contribution of IC in generating value for corporate reputation. Additionally, the study contributes to the literature on the link between IC and performance by examining a sample of firms not yet explored in prior research.


2019 ◽  
Vol 23 (1) ◽  
pp. 41-62 ◽  
Author(s):  
Valentina Ndou ◽  
Giovanni Schiuma ◽  
Giuseppina Passiante

PurposeThe creative process through which the territorial resources, knowledge and culture are used, exploited and configured to match needs and to achieve congruence with the changing business environment has become a crucial process for competitiveness. This is even more relevant for economies of developing countries which are continuously struggling to reap the benefits of globalisation, as well as to grasp the new opportunities for competitiveness. As such, this paper aims to try to concentrate on the dynamic perspectives of the creative economy of countries by distinguishing between the potentialities and performance. The paper tackles the influence that creativity capacities might have on performance of countries.Design/methodology/approachThe methodology consists in identifying creative economy indicators from a diverse data set of the World Economic Forum and distinguish them between potential and performance indicators.FindingsData reveal as good progress and emphasis is being devoted to increasing the level of creativity; however, the Balkan countries still holdup in their capacity to boost innovation.Practical implicationsThe paper provide a new focus of research on creativity measurement that is significant for understanding what creative capacities territories possess and the ability to make proficient use for growth and innovation.Originality/valueThis paper proposes a new operational framework for measuring and interpreting the creative economy indicators by identifying not only indicators that gauge the potentialities of a country, but also indicators that are linked with the performance dimension, as well as the relationship amongst them.


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